Although no pre-Ottoman archives have survived intact, scholars have recently demonstrated that Arabic documentary archives were carefully maintained by various actors during the Middle Ages. This paper examines the documents currently housed in the Coptic Patriarchate Archive in Cairo (CPA), specifically indirect evidence from extant communal endowment deeds (waqfiyyas), to reconstruct archival practices within these non-Muslim communal archives. These traces—from internal references to related legal documents, on the one hand, to ‘external’ markings, like archivists’ cross-referencing notations, on the other—allow us glimpses of a pre-Ottoman documentary culture with its unique social logic. The documents of the CPA are, by and large, endowment deeds issued by Islamic courts. The paper discusses the special import of this legal instrument (charitable endowment) to the long-term survival of dhimmī communities like the Coptic Christian community and the effects this had on Coptic archiving practices. Last but not least, the paper considers how Coptic reliance on such legal instruments (and their specific documentary forms) had on the ‘shape’ of these dhimmī communities and the nature of authority within them.